In the processing of produce such as fruits for canning it is normally necessary to grade the fruit and sort it by grades for ultimate appropriate labeling of cans or the like. At least some types of fruit are normally graded by color and this is conventionally carried out by inspectors visually viewing fruit passing along a sorting line and physically separating the fruit into various categories or grades. This type of sorting is not only time-consuming and expensive, but is also subject to fairly wide fluctuations and variations depending upon a number of human factors which in themselves are variable. Consequently, conventional color sorting of fruit is quite inexact.
Prior art attempts to automate color sorting operations have been at least partially successful in some fields, but to date, have not found acceptance in the field of fruit grading. Thus in the grading of peaches for canning, it is recognized that varying sizes and contours of peach halves, for example, involve problems not readily handled by conventional equipment. Further to this example, it is noted that peaches are normally graded as standard, choice, or fancy, depending upon the degree of ripeness and containers of canned peaches are marked for sale with an appropriate one of these appelations. The grading of peaches into these categories is carried out in accordance with the color of peeled peach halves prior to canning and conventionally the center grade, choice, has a yellow color with less ripe or greener fruit being denominated standard, and fully ripe fruit, denominated as fancy, having a yellow/orange color. Clearly, the differences in color are somewhat subjective, although governmental regulations may provide some basic grading criteria. Visual color sorting by human operators or inspectors is a poor manner of achieving reproduceable results, but to date, it is yet the best way known to the industry.